(a) Field of the Invention
The present invention generally relates to a fuel cell stack. More particularly, the present invention relates to an engaging structure of a fuel cell stack.
(b) Description of the Related Art
Generally, a fuel cell stack is an electricity generating device that converts the chemical energy of fuel and an oxidizing agent into electrical energy.
Such a fuel cell stack preferably includes a plurality of unit cells disposed one after another, and each unit cell generates electrical energy by using the fuel and the oxidizing agent.
In the fuel cell stack, a plurality of unit cells are suitably pressed by a pair of end plates disposed at upper and lower ends of the unit cells, and the pair of end plates are engaged to each other by a joining device.
According to a conventional joining device, the unit cells are suitably pressed by engaging the pair of end plates by using a bolt and a nut or by a steel band.
In the former case, since the end plates are engaged by the bolt and the nut, a dead volume of the end plates for engaging the bolt and the nut is increased. As a result, the fuel cell stack is unsuitable for mounting in a vehicle, and the fuel cell stack cannot be compact.
In the latter case, if the length of the fuel cell stack is changed by elastic characteristics or a size deviation of the stack, a band corresponding to the length should be provided. Therefore, workability for assembling the stack may be deteriorated.
Accordingly, there remains a need in the art for improved joining devices for fuel cell stacks.
The above information disclosed in this the Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.